The city’s archbishop, who was officiating at another church, said about 30 people had burst into the cathedral of St Gregory Palamas and, aside from interrupting mass, had “destroyed what they could”. He did not elaborate.

The cathedral is named after a 14th-century archbishop of Thessaloniki, who is revered in the Orthodox church.

Police said 19 men and seven women were arrested. Seventeen were Greek and the others were from Germany, England, Austria, Switzerland and Morocco.

They were protesting against a police operation in the city on Wednesday in which squatters and refugees were evicted from three illegally occupied buildings.

One of the buildings, formerly an orphanage, is the property of the Greek Orthodox church and is being demolished to build a hospice for the terminally ill, the archbishop said.

Police arrested 74 people during that operation, 64 of them foreigners. Thirty-three refugees were released.

An improvised device also exploded outside the offices of the construction company demolishing the church’s property before dawn on Sunday but did little damage.